Nitration of biodiesel by acetyl nitrate: Kinetic study and chemical safety parameters

Abstract

The aim of this study was to synthesize a bio-sourced substitute to the 2-Ethyl Hexyl Nitrate (EHN) by nitrating a biodiesel. EHN is commonly used to improve the auto-ignition properties of diesel fuels. The biodiesel was obtained by trans-esterification of canola oil. The nitration reaction of biodiesel by acetyl nitrate was carried out in a reaction calorimeter RC1 with semi-batch mode to study its kinetic and exothermic behavior and acetyl nitrate as nitrating agent. The impact of the synthesis temperature on the thermal behavior and on the reaction medium composition was investigated. The final product was analyzed by using several analytical techniques such as iodine value, infrared spectrometry, GC–MS. Three nitrated products have been identified: Methyl-8-nitro oleate, Methyl-10-nitrate-9-nitrostearate and 10-acetoxy-methyl-9-nitrostearate, whose selectivity depends on the synthesis temperature. A chemical model for nitration is proposed and the thermal power profiles released by the reaction mixture are used to estimate the energy and chemical kinetic parameters. Safety parameters, maximum temperature of the synthesis reaction (MTSR) and TD24 were also determined. In addition, a Cooperative Fuel Research (CFR) engine was used to analyze the cetane number of diesel fuel mixed with our additive. The results showed an increase in cetane number by 6 points.